Trucks having open rear cargo bays are typically backed into alignment with a loading dock or other doorway to facilitate loading and unloading of the vehicle. A significant space is typically formed between the truck and the building which exposes the interiors of the building and the truck, and the workers and materials to the outside environment during loading and unloading. Attempts to seal the gap have included loading dock shelters which have utilized fabric or sheet material to form walls and/or curtains between the opening and the truck and loading dock seals which utilize resilient, compressible pad members, generally disposed at the lateral and top edges of the opening, to sealably engage the exterior walls or rear edges of the truck.
Unfortunately, typical loading dock seals and shelters have several disadvantages. Since the dock seals which engage the rear edges of the truck must be disposed so that they overlap or extend into the truck's doorway to ensure that the rear edges of the truck engage the compressible pad members, they have reduced the size of the passageway, limiting access into the truck and generally inhibiting loading and unloading of the truck.
Conventional dock seals have also been unable to accommodate uneven truck surfaces, projecting hinges and the like and thus, have been unable to create an air tight seal. The same has been true for conventional dock shelters. With respect to the dock seals which seal against the exterior truck walls, a gap between open hinge-type doors and the truck body allows access of the outside environment to the loading area regardless of the tightness of the seal established between the dock seal and the exterior wall of the truck.
Many conventional dock seals are relatively difficult to maintain. Since many conventional dock seals have rigid right angles, they have been subject to impact damage from the trucks. Attempts to provide hinged dock seals or compressible frames have not been entirely satisfactory because they increase manufacturing costs. The compressible pads also require the truck to exert considerable force on the pad and the building wall in order to obtain the proper sealing engagement, increasing abrasion and wear on the seal and curtain materials, particularly where the rear corners and edges of the truck rub against the material.
Since many loading docks have inclined driveway grades, many loading dock shelters must be individually manufactured in order to accommodate such grades and maintain the proper perpendicular orientation between the truck walls and the seals. This increases manufacturing costs.